I. Field
The following description relates generally to wireless communications systems, and more particularly to a low complexity, unified processing technique for an uplink control channel in wireless communications systems.
II. Background
Wireless communication systems are widely deployed to provide various types of communication content such as voice and data, Typical wireless communication systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, . . . ). Examples of such multiple-access systems may include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP2, High Speed Packet Access (HSPA), High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), 3GPP long-term evolution (LTE), LTE Advanced (LTE-A), etc.
Generally, wireless multiple-access communication systems may simultaneously support communication for multiple mobile devices. Each mobile device may communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations.
A base station can transmit control information, or signaling, on a downlink control channel to one or more mobile devices. Similarly, a mobile device can transmit control information or signaling on an uplink control channel to the base station. Downlink control information can support associated downlink data transmissions. For instance, downlink control information can include scheduling assignments, information that facilitates demodulation and decode of downlink data transmissions, and the like. In addition, downlink control information can also include information that supports uplink transmissions. For example, downlink control information can include scheduling grants for resources on an uplink channel, hybrid automatic repeat request (ARQ) acknowledgments in response to uplink transmissions, and/or power control commands. Similarly, uplink control information can support uplink and/or downlink transmissions. For instance, uplink control information can include hybrid-ARQ acknowledgements associated with received downlink transmissions, reports on downlink channel conditions, scheduling requests, etc.
In Long Term Evolution (LTE), a physical uplink control channel (PUCCH) can be utilized to convey uplink control information. PUCCH is employed by a mobile device when the mobile device does not have a scheduling grant for resources on a physical uplink shared channel (PUSCH). A PUCCH resource consists of a single resource block, which can span 12 sub-carriers in the frequency dimension and 1 sub-frame in the time dimension. PUCCH employs frequency division multiplexing (FDM) between resource blocks and code division multiplexing (CDM) within a resource block. The combined FDM/CDM approach enables a plurality of mobile devices to employ a single PUCCH resource to transmit uplink control information to a base station.
As multiple mobile devices can utilize the same resources, the base station implements separation algorithms to isolate uplink control information from individual mobile devices. Conventionally, the base station employs a per-mobile device approach to separate users on the PUCCH resource. For instance, the base station executes an isolation technique multiple times depending on a number of mobile devices included in the uplink control channel. Such iteration and/or duplication of processing can lead to high-complexity receivers.